This project will develop a swept near-infrared light source that enables a portable hyperspectral tomographic functional optical imager. While such a device has many applications within endogenous NIR spectroscopy and imaging, or molecular imaging spectroscopy, we will focus on the application of the light source within an instrument designed for breast imaging. The long term goal is to develop a source that combines 5-10 individual chips to form a very compact (0.5 cm x 0.5cm x0.5cm) swept source with a range of 200-400nm, a scanning speed of 10-100msec and an output power of 10mW. This source would be incorporated into a handheld functional Diffuse Optical Spectroscopic Imaging device (not requiring exogenous contrast agents) to monitor and predict chemotherapy response in the treatment of breast cancer. A DOSI instrument developed at UC Irvine is currently undergoing validation on neoadjuvant patients in a multi-center clinical trial supported by the NIH. The swept NIR source would improve the performance and commercialization potential of a handheld DOSI instrument by allowing 3D subsurface imaging, improving the signal to noise ratio of the image by delivering a much higher photon intensity to the detector, and allowing the miniaturization of the device so that it is compatible with routine clinical use. The Phase I projet will demonstrate a swept optical source based upon an integrated VCSEL-MEMs technology. The output optical wavelength of the device will be centered at 850nm, and will demonstrate an output power of 1mW, and a tuning range of 35nm with a tuning rate of 10msec. During the Phase I project, this initial prototype device will be inserted into a DOSI handheld probe and will be used to measure the optical properties in a breast tissue simulating phantom. The phase II project will optimize the device performance, and extend it to the full range of wavelengths (multiple VCSEL- MEMs die that together span the entire desired wavelength range) and will be implemented in a handheld imager to demonstrate full imaging functionality. PUBLIC HEALTH RELEVANCE: This project will develop an optical light source that enables improved tomographic functional optical imaging for detecting, characterizing and therapeutic monitoring of breast cancer. Key applications include screening for breast cancer for younger women, as well as monitoring the effectiveness of neoadjuvant chemotherapy. The optical source is expected to enable improved image signal to noise, contrast, and imaging depth.